Method for manufacture of corrugated boards

ABSTRACT

A method and apparatus suited for manufacture of corrugated boards whose pitches, heights and profiles of corrugations may be varied in a simple manner during the course of manufacture. Opposed to the conventional method and apparatus wherein a flat sheet or sheets are adhered to one or both sides of a corrugated sheet which is formed by corrugating rolls or the like, a sheet is reciprocated between a pair of spaced apart flat sheets while they are advanced, thereby adhering the corrugated sheet alternately to the flat sheets. By varying the amplitude or stroke of the reciprocal movement of the sheet, the heights of corrugations may be varied while the pitches of corrugation can be varied by varying the feed of both flat sheets during the time when the sheet to be corrugated moves from one flat sheet to the other, that is the line of adhesion of one flat sheet to the other. Profiles of corrugations may be varied by varying the widths (in the direction of advancement of the sheet to be corrugated) of adhesion between the corrugated sheet and the flat sheets, thereby varying the cross sections of corrugations into rectangular, trapezoid, etc. The invention may use not only paper board but also synthetic resin sheets.

y 1-972 RINNOSUKE susuKl ETAL METHOD FOR MANUFACTURE OF CORRUGATED BOARDS 4 Sheets-Sheet Filed Feb.

July 18, 1972 RINNOSUKE SUSUKI ETAL 3,677,857

METHOD FOR MANUFACTURE OF CORRUGATED BOARDS 4 Sheets-Sheet 2 Filed Feb. 18

Juiy 18, 1972 RINNOSUKE susum ETAL 1 1 METBOD FOR MANUFACTURE OF CORRUGATED BOARDS Filed Feb. 16 1970 4 Sheets-Sheet 5 I III.

July 18, 1972 RINNOSUKE SUSUKI ETAL METHOD FOR MANUFACTURE OF CORRUGATED BOARDS Filed Feb. 16. 1970 4 Sheets$heet 4 United States Patent Office Int. Cl. B31r 1/22 US. Cl. 156-210 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus suited for manufacture of corrugated boards whose pitches, heights and profiles of corrugations may be varied in a simple manner during the course of manufacture. Opposed to the conventional method and apparatus wherein a fiat sheet or sheets are adhered to one or both sides of a corrugated sheet which is formed by corrugating rolls or the like, a sheet is reciprocated between a pair of spaced apart fiat sheets while they are advanced, thereby adhering the corrugated sheet alternately to the flat sheets. By varying the amplitude or stroke of the reciprocal movement of the sheet, the heights of corrugations may be varied while the pitches of corrugations can be varied by varying the feed of both fiat sheets during the time when the sheet to be corrugated moves from one flat sheet to the other, that is the line of adhesion of one flat sheet to the other. Profiles of corrugations may be varied by varying the widths (in the direction of advancement of the sheet to be corrugated) of adhesion between the corrugated sheet and the flat sheets, thereby varying the cross sections of corrugations into rectangular, trapezoid, etc. The invention may use not only paper board but also synthetic resin sheets.

BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for manufacture of corrugated boards and as a product thereof a corrugated board having a fiat sheet or sheets adhered to one or both sides of a corrugated sheet and more particularly a method and apparatus for manufacture of corrugated boards not only from paper board but also from synthetic resin sheets, the pitches, heights and profiles of corrugations of the corrugated boards being arbitrarily adjusted in the course of manufacture.

In the conventional method, the sheets are first corrugated by corrugating rolls or the like and a fiat sheet or sheets are adhered to one or both sides of these corrugated sheets, thereby providing corrugated boards. To vary the pitches of corrugations, the apparatus must be temporarily stopped during the time when the corrugating rolls having a desired pitch are replaced. In manufacture of corrugated boards made of synthetic resin sheets, the backing members having the mating corrugations must be placed at the back of the corrugated sheet when a fiat sheet is welded thereto, so that both of the sheets may be firmly pressed against each other, thereby obtaining a suflicient adhesion therebetween. But when it is desired to adhere another flat sheet on the other side of the corrugated sheet, they cannot be directly pressed against each other by heating means when they are thermally welded together, so that a suificient adhesion is not attained.

SUMMARY OF THE INVENTION In view of the above, the primary object of the present invention is to provide a method and apparatus best suited Patented July 18, 1972 for manufacture of corrugated boards whose pitches, heights and profiles of corrugations may be easily varied even during the course of manufacture.

Another object of the present invention is to provide a method and apparatus for manufacture of corrugated boards made of synthetic resin sheets so that sufficient adhesion may be attained in case of thermal welding.

A further object of the present invention is to provide a method and apparatus for manufacture of corrugated boards made of synthetic resin sheets, said corrugated boards having corrugations whose pitches, heights and profiles may be partially varied.

I In brief, the present invention provides a method for manufacture of corrugated boards comprising the steps of advancing a sheet to be corrugated between a pair of spaced apart fiat sheets, and reciprocating said sheet to be corrugated between said pair of spaced apart flat sheets in the direction perpendicular to the direction of advancement of said sheet to be corrugated, thereby alternately contacting said first mentioned sheet with said pair of spaced apart flat sheets and adhering all of said sheets into a corrugated board.

The present invention provides an apparatus for carrying out the method thereof, said apparatus comprising a pair of feed rollers for advancing a sheet to be corrugated, two pairs of feed rollers each for advancing each of flat sheets to be adhered to both sides of the corrugated sheet, heating or pressure roller means which are reciprocated by a suitable mechanism so as to cause the reciprocal movement of said first mentioned sheet at a right angle with respect to the advancement thereof between said two pairs of feed rollers spacing of which is adjustable, thereby adhering the corrugated sheet to the fiat sheets when they are contacted with each other by said reciprocal movement by said heating rollers or adhesive agent application means with the aid of said pressure rollers, and means for discharging thus fabricated corrugated board in contact therewith.

By varying the stroke of the reciprocal'movement or the spacing between the two pairs of feed rollers, the heights of corrugations may be varied; by varying the feed of two flat sheets relative to the reciprocal movement of the sheet to be corrugated, the pitches of corrugations may be varied; and by varying the adhesion areas between the corrugated sheet and the fiat sheets, the profiles of corrugations may be varied in the course of manufacture.

The above and other objects, features and advantages of the present invention will become more apparent from the description of some illustrative embodiments thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 and 2 are diagrammatic views of a first and second embodiment of the present invention; and FIGS. 3 to 7 are sectional views of corrugated boards fabricated in accordance with the method and apparatus of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a sheet Sc to be corrugated is guided by a pair of guide rollers 1. Two pairs of feed rollers generally indicated by 2 and each comprising rollers 21 and 22 are disposed for feeding flat sheets S-1 and 8-2 which are bonded or welded to one or both sides of the corrugated sheet Sc. A pair of heating rollers 31 and 32 which are maintained at an elevated temperature by suitable heating means (not shown) are adapted to be reciprocated horizontally in FIG. 1 along a guide 33 with the sheet Sc being interposed between the pair of heating rollers 31 and 32. The guide 33 is provided with a rack 4 formed at one side thereof and in mesh with asector gear 53 which is pivotably fixed by a pivot 51. One end 61 of an arm 6 which is reciprocated by suitable means (not shown) is so pivotably fixed to an arm 52 that the pivotal point 61 may be selectively displaced in the axial direction of the arm 5. A corrugated sheet drawing device generally designed by 7 is comprised of a pair of drive rollers 71 and 72 and a belt 73 which is wrapped thereover and advanced in the direction of advancement of the corrugated board at the same speed in contact therewith, so that the corrugated board may be drawn or advanced. Next the mode of operation of the first embodiment will be described hereinafter. When the sheet Sc and flat sheets S-1 and 8-2 are advanced by means of the pair of guide rollers 1 and two pairs of feed rollers 2 respectively, the heating rollers 31 and 32 are reciprocated so as to contact with the. feed rollers 21 by the reciprocal motion of the reciprocating rod 6. Upon contact of the heating rollers 31 and 32 with the feed rollers 21, the latter are stopped while the heating roller 31 or 32 is firmly pressed against the feed roller 21 by suitable resilient means (not shown). Therefore the corrugated sheet So is welded to the flat sheets S-1 and 8-2 along the lines of contact of the heating rollers 31 and 32 with the feed rollers 21. It is therefore readily seen that upon reciprocal movement of the heating rollers 31 and 32, the three sheets Sc, S-1 and 8-2 are Welded into corrugated board and thereafter withdrawn by the corrugated board drawing devices 7.

Referring next to FIG. 2, a second embodiment of the present invention will be described in more detail hereinafter. The second embodiment is adapted to adhere the flat sheets 8-1 and 8-2 to both sides of the corrugated sheet Sc by an adhesive agent instead of welding in the first embodiment. It should be noted that same reference numerals as those used in FIG. 1 are used to designate same parts in FIG. 2. In the second embodiment, it is noted that the heating rollers 31 and 32 are not provided with heating means, but they serve as pressure rollers.

A device for applying an adhesive agent to the lines of contact between the corrugated sheet Sc and the flat sheets S1 and 8-2 is also disclosed. The device includes an adhesive supply roller 82 which is immersed into an adhesive container 81 and an adhesive agent application roller 83 which is adapted to rotate in contact with the adhesive supply roller 82. The adhesive application device is reciprocated through a suitable crank mechanism as a whole. That is, upon reciprocation of a rod 84, the application roller 83 is moved toward and away from the outer periphery of the guide roll 21 so that the application roller 83 may contact with the fiat sheet S-2 which is being advanced over the roller 22. The contact time must be so selected as to produce a desired pitch of corrugations. Next the method which is believed to be characteristic of the present invention for 'varying the pitches of corrugations, the heights thereof, that is the thickness of corrugated boards and the profiles of corrugations will be described hereinafter. From FIGS. 1, 2, 3 and 4, it is readily understood that the thickness of the corrugated board may be varied by adjusting the spacing between the two pairs of feed rollers 2 While the stroke of the heating or pressure rollers 31 and 32 are suitably adjusted depending upon the spacing. For example in the first embodiment, the pivot 61 of the rod 6 is displaced so as to vary so that the reciprocal motion of the rod 6 may produce an eccentric crank motion. The pitches of corrugations p may be varied by varying the distances of the flat sheets S-1 and 8-2 during the time when the corrugated sheet Sc is moved away from one welding line B at which thecorrugated sheet Sc is welded to one of the flat sheet S-1 or 8-2 to the next welding line B at which the corrugated sheet Sc is welded to the other flat sheet 8-2 or 8-1 by the heating rollers 31 and 32 and the feed rollers 21.

Referring to FIG. 3, when it is desired to form the sheet Sc into trapezoid shape, that is to provide the corrugated board in the form of truss, the feed rollers 21 and 22 are still driven even when they are made in contact with the heating or pressure rollers 31 and 32. (It should be noted that when the sheets Sc, S-1 and S-2 are bonded or welded together along the lines of contact, the feed rollers 21 and 22 are stopped as described hereinabove.)

According to the present invention, the corrugated board having a special construction as shown in FIG. 5 may be provided in a simple manner. As shown in FIG. 5, the pitches of corrugations 'within the range indicated by L are smaller than those in other section of the corrugated board. The embodiment shown in FIG; 5 may be very advantageously used when the small corrugation pitch section L of the corrugated board is so placed as to cover the important parts or sections of a machine when it is packed so that the important parts or sections may be firmly and effectively protected from for example an excess impact. I

Referring to FIGS. 6 and 7, the method and apparatus in accordance with the present invention can provide also corrugated boards having special constructions. In a variation shown in FIG. 6 which is opposed to the above described embodiments, one flat sheet or sheets are not bonded or welded over the whole surface or surfaces of the corrugated sheet Sc, but strip-shaped sheets 8-11, 8-12 and so on are bonded or welded to one side of the corrugated sheet Sc in equidistantly spaced apart relation with each other while the similar sheets S-21, S-22 and so on are bonded or welded to the other surface of the corrugated sheet Se in equidistantly spaced apart relation with each other. It should be noted that the longitudinal direction of each sheet bonded or welded to the corrugated sheet Sc is in parallel with the direction of advancement thereof.

In a variation shown in FIG. 7, the strip-shapedsheets S-21, 8-22 and so on are bonded or welded to one side of the corrugated sheet Sc in the similar manner as the corrugated board shown in FIG. 6, but a flat sheet 8-1 is bonded or welded to the other side of the corrugated sheet Se in the case of the embodiments described here: inabove. However, it should be noted that the fiat sheet 8-1 is bonded or welded to the ridges of the corrugated sheet Sc whose opposed faces have no strip-shaped sheets S-21, S-22 and so on bonded or Weldedthereto. In both of the variations shown in FIGS. 6 and 7, the strip-shaped sheets bonded or welded to the corrugated sheet Sc serve to prevent the collapse of the corrugations even though they are not bonded or welded to the Whole surfaces of the corrugated sheet Sc so that the impact absorbing characteristic of the corrugated board may be well ensured. Furthermore, it is seen that the bonding or welding time may be much saved. From the foregoing, it is seen that in accordance with the present invention, the pitches of corrugations, the thickness of corrugated boards and the profiles of corrugations may be arbitrarily varied as needs demand without replacing the corrugating rolls as required in the conventional method. The present invention has been so far described with particular reference to some illustrative embodiments thereof, but it will be understood that variations and modifications can be efiected Without departing from the true spirit of the present invention as described hereinabove and as dc fined in the appended claims.

What is claimed is:

1. A method for manufacture of corrugated boards comprising the steps of: feeding separately a sheet to be corrugated and a pair of spaced fiat sheets advancing and reciprocating said sheet to be corrugated between said flat sheets to alternately contact the sheet to be corrugated with said fiat sheets thereby adhering all of said sheets into a corrugatedboard; and discharging the corrugated board so produced with both sides thereof being supported in the direction of advancement of the corrugated board at the same speed therewith, the improvement wherein said sheet to 'be corrugated is reciprocated in the direction perpendicular to that of the advancement thereof and is supported and interposed by a pair of pressing sources while a pair of adhesive sources is similarly reciprocated toward and away from the outside of said flat sheet which are spaced at an equal distance to each other in an adhering cycle corresponding to the desired pitch of corrugations, wherein said sheet to be corrugated is simultaneously adhered and pressed firmly against said fiat sheets in cooperation with said pressing sources and a pair of feeds for said fiat sheets along the lines of contact while stopping the feed of these fiat sheets.

2. A method as claimed in claim 1 of varying the thickness of the corrugations wherein the spacing between said fiat sheets is adjusted and the stroke reciprocating said sheet to be corrugated is also adjusted.

3. A method as claimed in claim 1 of varying the pitch of the corrugations by adjusting the feed of said flat sheets during the time when said sheet to be corrugated is moving away from one adhesion line at which the sheet is adhered to one fiat sheet u to the next successive adhesion line at which the sheet is adhered to the other fiat sheet.

4. A method as claimed in claim 1 of varying the profiles of the corrugations by continuously feeding said fiat sheets while they are adhered and pressed firmly against said sheet to be corrugated in contact therewith.

5. A method for the manufacture of corrugated boards comprising the steps of feeding separately a sheet to be corrugated and a pair of spaced flat sheets advancing and reciprocating said sheet to be corrugated between said fiat sheets to alternately contact said sheet to be corrugated with said flat sheets, thereby thermally welding together all three of said sheets into a corrugated board; and discharging the corrugated board so produced with both sides thereof being supported in the direction of advancement of the corrugated board at the same speed therewith, the improvement wherein said sheet to be corrugated is reciprocated in the direction perpendicular to that of the advancement thereof between said flat sheets which are arranged at an equal distance to each other, while being supported and interposed by a pair of heating sources, wherein said sheet to be corrugated is simultaneously thermally welded and pressed firmly against said flat sheets in cooperation with said heating sources and feeding means of said fiat sheets along the lines of contact while stopping the feed of these flat sheets.

6. A method as claimed in claim 5 of varying the thickness of the corrugations wherein the spacing between said flat sheets is adjusted and the stroke reciprocating said sheet to be corrugated is also adjusted.

7. A method as claimed in claim 5 of varying the pitch of the corrugations by adjusting the feed of said fiat sheets during the time when the sheet to be corrugated is welded thermally to one flat sheet up to the next successive welding line at which the sheet to be corrugated is Welded thermally to the other fiat sheet.

8. A method as claimed in claim 5 of varying the profiles of the corrugations by continuously feeding the flat sheets while they are in contact with said sheet to be corrugated to be welded thermally and pressed firmly against said sheet.

9. A method for manufacture of corrugated boards comprising a first flat sheet, a second flat sheet and a corrugated sheet therebetween, said corrugated sheet secured to both of said flat sheets, including the steps of:

(a) feeding a pair of flat sheets together in a direction parallel to and spaced apart from each other;

(b) separately feeding the sheet to be corrugated between the first and second fiat sheets and reciprocating the sheet to be corrugated in a direction perpendicular to the advancement of the pair of fiat sheets of step (a) while supporting and interposing the sheet to be corrugated by a pair of pressing sources and While intermittently contacting a pair of adhesive sources with that surface of the first fiat sheet and the second fiat sheet to be contacted with the sheet to be corrugated, thereby alternatively contacting the sheet to be corrugated with each of the adhesive-carrying flat sheets;

(c) adhering both of the first fiat sheet and the second flat sheet to the corrugated sheet in an adhering cycle corresponding to the predetermined pitch of the corrugations by pressing the sheet to be corrugated firm- 1y, first against the first flat sheet and then against the second flat sheet, and adhering the three sheets together, simultaneously with step (b);

(d) stopping the feed of step (a) while sheet to be corrugated is in contact with either of the first flat sheet or the second flat sheet, and resuming the feed of step (a) when the sheet to be contacted is no longer in contact with either the first fiat sheet or the second fiat sheet;

(e) removing the corrugated board so produced in the direction of the advancement of step (a) and at the same speed therewith.

10. A method for manufacture of corrugated boards comprising a first flat sheet, a second fiat sheet and a corrugated sheet therebetween, said corrugated sheet thermally welded to both of said flat sheets, including the steps of:

(a) feeding a pair of flat sheets together in a direction parallel to and spaced apart from each other;

(b) separately feeding the sheet to be corrugated between the first and second flat sheets and reciprocating the sheet to be corrugated in a direction perpendicular to the advancement of the pair of flat sheets of step (a) while supporting and interposing the sheet to be corrugated by a pair of heating sources, thereby alternately contacting the sheet to be corrugated with each of the fiat sheets;

(0) thermally welding both of the first fiat sheet and the second flat sheet to the corrugated sheet in an adhering cycle corresponding to the predetermined pitch of the corrugations by pressing with the respective heating source the sheet to be corrugated firmly, first against the first flat sheet and then against the second flat sheet, thereby thermally welding the three sheets together, simultaneously with step (b);

(d) stopping the feed of step (a) while the sheet to be corrugated is in contact with either of the first flat sheet or the second fiat sheet, and resuming the feed of step (a) when the sheet to be contacted is no longer in contact with either the first flat sheet or the second flat sheet;

(e) removing the corrugated board so produced in the direction of the advancement of step (a) and at the same speed therewith.

References Cited UNITED STATES PATENTS 3,010,508 11/1961 Wilson et al. 1562l0 X 3,053,722 9/1962 Petty 156210 BENJAMIN A. BORCHELT, Primary Examiner G. E. MONTONE, Assistant Examiner US. Cl. X.R. l56-470, 474 

